1. Field of the Invention
The present invention relates to an improved process for preparing an aldehyde or ketone from an ethylenically unsaturated compound.
2. Description of the Prior Art
The invention relates to an improvement in the prior art process for the preparation of an aldehyde or a ketone by ozonolysis of an ethylenically unsaturated compound with a gaseous mixture comprising ozone and oxygen or air mixture followed by reductive cleavage of the ozonolysis product obtained, and to the aldehydes or ketones so prepared.
The above prior art process often yields appreciable amounts of carboxylic acids and rearrangement products. For example, as described in U.S. Pat. No. 3,708,528, 4-acetyl-2-carene (named hereinafter "compound A"). ##STR1## is ozonolyzed with a gaseous mixture containing ozone and oxygen and the ozonolysis product thus formed is subjected to reductive cleavage with formation of 2-(2-acetyl-3-oxobutyl)-3,3-dimethylcyclopropanecarbaldehyde (named hereinafter "compound B"). ##STR2## but analysis by the applicants of the reaction mixture formed by the reductive cleavage has shown that compound B is formed in a low yield, the mixture also containing considerable amounts of 2-(2-acetyl-2-hydroxy-3-oxobutyl)-3,3-dimethylcyclopropanecarbaldehyde (named hereinafter "compound C"), 2-(2-methoxycarbonylpropyl)-3,3-dimethylcyclopropanecarbaldehyde (named hereinafter "compound D") ##STR3## and 2-(2-acetyl-3-oxobutyl)-3,3-dimethylcyclopropanecarboxylic acid (named hereinafter "compound E"). ##STR4##
Thus, compound A is converted by this known process into a complicated mixture of four compounds.
It has now been found that when the ozonolysis is carried out in the presence of a special compound the aldehydes or ketones are usually obtained in an attractively high yield and formation of carboxylic acids and rearrangement products is suppressed.